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In this study an extensive experimental campaign has been conducted on mortars modified with nano-Graphite (nG) aimed to assess the properties of the resulting nanocomposites in terms of density, microstructure, flexural and compressive strength, damping ratio, thermal and electrical conductivity. Permeability properties were also investigated in terms of initial surface absorption, water contact angle, volume of permeable voids and chloride ion diffusion. Premixed mortars have been modified with different dosages of commercial nG, i.e. 0.01%, 0.1%, or 0.2% by weight of cement. The rheological behavior of the fresh admixtures has been investigated. Specimens were casted in bars and hardened in water for 7, 14 or 28 days. At 28 days all samples showed enhanced density (i.e. up to 16%) and mechanical properties (i.e. up to 30%) combined to remarkable decreased overall permeability. The lowest dosage of nG (i.e. 0.01% by weight of cement) resulted in cement nanocomposites with the highest increase in damping ratio, electrical and thermal conductivity, 68%, 30% and 55%, respectively.

Several proton conductive ceramic oxides are evaluated for potential application in ceramic-NiO composite anodes for proton-conducting La0.99Ca0.01NbO4 (LNO) electrolyte-based fuel cells. Chemical compatibility tests show that most of the existing proton-conducting oxides are unfavorable for application in LNO electrolyte-based fuel cells because of undesirable reactions at high temperatures. Further considering the chemical compatibility with NiO and the ability to promote the densification of the deposited LNO electrolyte, LNO-NiO composite anode proves to be the only suitable anode candidate. With humidified hydrogen (∼3%H2O) as the fuel and static air as the oxidant, fuel cells based on LNO electrolyte film deposited on LNO-NiO anodes show a peak power density of 24 mW cm−2 at 750 °C, this value being one of the largest ever reported for LNO-based cells. Further investigation reveals that the polarization resistance of the cell is the major contribution to the total cell resistance, limiting the overall cell performance.

Commercially available FFF machines have limitations in process reliability and quality of the products. The live monitoring of the 3D printing process could improve quality and the produced part performance. In the present work, a print-head integrated system, based on optical and thermal sensors, for live monitoring of a FFF 3D printing process was developed. A Design of Experiments (DoE) campaign has been set in order to optimize the printing process parameters for polyamide 6 (PA6), starting from the analysis of the acquired data. Experimental results show that optical and thermal cameras allow to detect invisible to naked eye defects, such as warping, incorrect filament deposition, stringing and oozing. Moreover, the thermal data have been successfully used to calculate the cooling kinetics of the different layers of a job, providing direct information related to degree of crystallinity. From DoE campaign the bed temperature has been found to be the most influential process parameter affecting morphology and mechanical properties of 3D printed samples. Optimized samples show an increase of young modulus and tensile strength up to 70% and 79% respectively compared to not optimized samples.

Neodymium-Iron-Boron (NdFeB) permanent magnets are essential components in many mechanical, electric and electronic devices, providing large magnetic fields with no energy consumption. Nevertheless, their poor corrosion resistance is an important issue that makes them susceptible to degradation of the magnetic properties. In this paper, the authors propose the preparation of NdFeB – Poly-ether-ether-ketone (PEEK) composites, with the dual target of protecting the magnetic alloy, preventing it from corrosion, while realizing a new 3D printable material, to produce high performance magnets with customized and optimized design. PEEK – NdFeB filaments were produced with different filler amount (15, 34 and 41 vol%). 3D printed bonded magnets were successfully produced, resulting in magnetic remanence of 82, 218, and 226 mT respectively, as well as intrinsic coercivity of 627, 684 and 672 kA/m. The influence of the filler on the thermal and mechanical properties of the resulting composites were evaluated by means of several investigation techniques.

Reversible solid oxide cells (RSOCs) represent a promising technology for the efficient exploitation of intrinsically intermittent renewable energy sources. RSOCs allow to derive fuel and chemicals from power (power-to-gas technology, P2G) and power from fuel and chemicals (gas-to-power technology, GTP) and can be interchangeably operated either as a solid oxide fuel cell (SOFC) or as a solid oxide electrolyzer cell (SOEC). The key aspect to render these devices competitive on a market scale is the development of multi-tasking, reliable, cost-effective and long-lasting electrodes (1,2). Besides, to overcome the issues related to hydrogen production, storage and distribution (e.g. impractical conversion of the existing grid to hydrogen-based infrastructures), the fuel-electrode of RSOCs should ensure high catalytic activity and coking resistance toward carbon-containing species (3-4). Using a hydrocarbon-tolerant fuel electrode, energy can be obtained by natural gas and biogas (SOFC-mode), with useful recovery of CO2 in the exhausts (carbon capture and storage, CCS). Besides, if the electrode is also active towards CO2 electrolysis (SOEC mode), CO2 is reduced to CO and O2 (carbon capture and utilization, CCU). Ni-YSZ is the reference fuel-electrode material for both H2 fed SOFC and for CO2 electrolysis in SOEC. Nevertheless, Ni-based cermets cannot be used in SOFCs fed with methane-containing fuels, as they suffer from two main drawbacks: mechanical instability upon NiO-Ni redox cycles (5) and passivation due to coking, being Ni a catalyst for methane cracking (3, 4). Moreover, during Ni-YSZ operation in CO2-SOEC mode, ZrO2 reduction can occur at high cathodic potential, resulting in Ni-Zr compounds formation (6). In this work, a recently developed (7, 8) composite material containing La0.6Sr0.4Fe0.8Mn0.2O3-δ (LSFMn) and 5wt% Ni-containing Ce0.58Sm0.15O2-δ (NiSDC) is tested as fuel electrode for LSGM-electrolyte supported cells. In reducing conditions, Fe exsolved from the LSFMn perovskite forms a Fe-Ni alloy with Ni present on SDC. In SOFC mode, the composite is designed to operate in dry methane: Fe-Ni catalytic sites activate CH4, which is successively oxidized on Mn-containing LSFMn, while SDC increases the O2- supply at the anode to get rid of any carbonaceous deposits. As Fe-Ni alloy was reported to be highly active for CO2 reduction (9), the composite was also tested as SOEC cathode in different CO2:CO ratios. LSFMn+NiSDC was tested in SOFC-mode as anode for hydrogen, dry methane and carbon monoxide oxidation and showed power density outputs of 657, 668 and 527 mW/cm2, respectively (Fig. a), a redox stable behavior and coking resistance for over 120 h. LSFMn+NiSDC in SOEC-mode delivered 2.66 A/cm2 at 2 V in 95:5 CO2:CO mixture (Fig. b), keeping 1 A/cm2 of current density output for over 40 h. (1) - M. Mogensen, M. Chen, H. Frandsen, C. Graves, J. Hansen, K. Hansen, A. Hauch, T. Jacobsen, S. Jensen, T. Skafte, Reversible solid-oxide cells for clean and sustainable energy, Clean Energy, 3 (2019) 175-201. (2) - M.B. Mogensen, Materials for Reversible Solid Oxide Cells, Current Opinion in Electrochemistry, (2020). (3) - M. Mogensen, K. Kammer, Conversion of hydrocarbons in solid oxide fuel cells, Annual Review of Materials Research, 33 (2003) 321-331. (4) - S. McIntosh, R.J. Gorte, Direct hydrocarbon solid oxide fuel cells, Chemical reviews, 104 (2004) 4845-4866. (5) - J. Malzbender, R. Steinbrech, Advanced measurement techniques to characterize thermo-mechanical aspects of solid oxide fuel cells, Journal of Power Sources, 173 (2007) 60-67 (6) - A. Hauch, K. Brodersen, M. Chen, M.B. Mogensen, Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability, Solid State Ionics, 293 (2016) 27-36 (7) - L. Duranti, I. Luisetto, S. Licoccia, C. Del Gaudio, E. Di Bartolomeo, Electrochemical performance and stability of LSFMn+ NiSDC anode in dry methane, Electrochimica Acta, (2020) 137116. (8) - L. Duranti, I.N. Sora, F. Zurlo, I. Luisetto, S. Licoccia, E. Di Bartolomeo, The role of manganese substitution on the redox behavior of La0.6Sr0.4Fe0.8Mn0.2O3-δ, Journal of the European Ceramic Society, (2020) ( 9 ) - Liu, S., Liu, Q., & Luo, J. L. (2016). Highly stable and efficient catalyst with in situ exsolved Fe–Ni alloy nanospheres socketed on an oxygen deficient perovskite for direct CO2 electrolysis. ACS Catalysis, 6(9), 6219-6228. Figure 1

The health monitoring of structures is of great interest in order to check components’ structural life and monitor damages during operation. Self-monitoring materials can provide both the structural and monitoring functionality in one component and exploit their piezoresistive behavior, namely, the variation of electrical resistivity with an applied mechanical strain. In this work, self-monitoring plies were developed to be inserted into glass-fiber reinforced epoxy-based laminates in order to achieve structural monitoring. Nanocomposite epoxy-based resins were developed employing different contents of high surface area carbon black (CB, 6 wt%) and multiwall carbon nanotubes (MWCNT, 0.75 and 1 wt%), and rheologically and thermomechanically characterized. Self-monitoring plies were manufactured by impregnating glass woven fabrics with the resins, and were laminated with non-sensing plies via a vacuum-bag process to produce sensored laminates. The self-monitoring performance of the laminates was assessed during monotonic and cyclic three-point bending tests, as well as ball drop impact tests. A higher sensitivity was found for the CB-based systems (Gauge Factor 6.1), while MWCNTs (0.55 and 1.04) ensure electrical percolation at lower filler contents, as expected. The systems also showed the capability of being used to predict residual life and damage occurred under impact.

An innovative concept of a low-cost pH optode with working volumes of less than 150 µL is presented. The pH monitoring is based on the color changing effect of pH indicators. The optode includes an RGB color sensor patch TCS34725 from Adafruit, a controllable LED and reactor slides and is addressed by a self-written LabVIEW© software. Utilizing the hue value of the HSV color model, it is possible to analyze the color change of the indicator and estimate the pH value of the analyzed samples by exploiting sigmoidal fit models. Measurements carried out with phenol red and DMEM (Dulbecco's Modified Eagle's Medium) reported a standard error of calibration in the physiologic pH range (6.5–7.5) of ±0.04 pH units.

In the present study, morphological and electrical properties of BaZrO3 were investigated as a function of the ionic radii mismatch between Zr and the different B-site dopants (Al, Sc, In, Lu, Tm, Y, Gd, Sm, Nd, and La) for the same solute concentration and valence. Our study highlights the critical role of the ionic radius of the acceptor dopant on stability, sinterability, and proton conductivity of barium zirconate. From our study, Gd-doped barium zirconate emerges as a novel promising material for proton conductor electrolytes.

In this work, hydrophilic silver nanoparticles (AgNPs), bifunctionalized with citrate (Cit) and L-cysteine (L-cys), were synthesized. The typical local surface plasmon resonance (LSPR) at &lambda, max = 400 nm together with Dynamic Light Scattering (DLS) measurements (&lt, 2RH&gt, = 8 &plusmn, 1 nm) and TEM studies (&Oslash, = 5 &plusmn, 2 nm) confirmed the system nanodimension and the stability in water. Molecular and electronic structures of AgNPs were investigated by FTIR, SR-XPS, and NEXAFS techniques. We tested the system as plasmonic sensor in water with 16 different metal ions, finding sensitivity to Hg2+ in the range 1&ndash, 10 ppm. After this first screening, the molecular and electronic structure of the AgNPs-Hg2+ conjugated system was deeply investigated by SR-XPS. Moreover, in view of AgNPs application as sensors in real water systems, environmental safety assessment (ecosafety) was performed by using standardized ecotoxicity bioassay as algal growth inhibition tests (OECD 201, ISO 10253:2006), coupled with determination of Ag+ release from the nanoparticles in fresh and marine aqueous exposure media, by means of ICP-MS. These latest studies confirmed low toxicity and low Ag+ release. Therefore, these ecosafe AgNPs demonstrate a great potential in selective detection of environmental Hg2+, which may attract a great interest for several biological research fields.

Copper and gadolinium doped ceria (GDC) anode supported fuel cells were co-sintered at relatively low temperature (900 °C) and successfully tested in the intermediate temperature (IT) range. The GDC electrolyte densification was promoted by a compressive strain induced by increasing the anodic thickness and was evaluated by SEM investigation. Instead of more commonly used La0.8Sr0.2Fe0.6Co0.4O3-δ, strontium and copper-doped lanthanum ferrite La0.8Sr0.2Fe0.8Cu0.2O3-δ (LSFCu) mixed with 30 wt% GDC (LSFCu-GDC) was employed as cathodic material. Preliminary tests on Cu-GDC/GDC/LSFCu-GDC single cells showed promising results at temperature as low as 650 °C using hydrogen as fuel.

High materials costs and low performance are the persisting bottlenecks that significantly affect the microbial fuel cells (MFCs) applications. The membraneless single-chamber MFC with an air-breathing cathode is a simple configuration where the bacteria play a role in both the anodic and cathodic processes. However, the microbial cathodic semi-reaction is the rate-determining step that can impair the advantage of the natural availability of oxygen in the air. In this work, the microbial catalysis was improved adding cerium oxide nanoparticles (nanoceria) in carbon-based cathodes of air-breathing MFCs, boosting their performance. Two kinds of nanoparticles were tested: CeO2 and Sm-doped CeO2 (Sm-CeO2) on carbon powder, using pristine carbon powder cathodes as a control. The energy generated was 113, 65 and 31 mWh m−2, for Sm-CeO2, CeO2 and control MFCs, respectively, during four subsequent fed cycles of 0.036 mol L−1 Na-acetate in carbonate buffer solution. The better performance of MFCs was correlated to the oxygen preferential and controlled entrapping and release via Ce4+/3+ redox reaction at the carbon particle surface, as well as to the increased cathode active specific surface area. The achieved results suggest that nanoceria can act as oxygen storage for bacteria in the anaerobic biofilm colonizing the cathode.

Multilayered heterostructures of Ce0.85Sm0.15O2-delta and Y0.16Zr0.92O2-delta of a high crystallographic quality were fabricated on (001) - oriented MgO single crystal substrates. Keeping the total thickness of the heterostructures constant, the number of ceria-zirconia bilayers was increased while reducing the thickness of each layer. At each interface Ce was found primarily in the reduced, 3+ oxidation state in a layer extending about 2 nm from the interface. Concurrently, the conductivity decreased as the thickness of the layers was reduced suggesting a progressive confinement of the charge transport along the YSZ layers. The comparative analysis of the in-plane electrical characterization suggests that the contribution to the total electrical conductivity of these interfacial regions is negligible. For the smallest layer thickness of 2 nm the doped ceria layers are electrically insulating and the ionic transport only occurs through the zirconia layers. This is explained in terms of a reduced mobility of the oxygen vacancies in the highly reduced ceria.

We have synthesized two-dimensional carbon nanoparticles by oxidative unfolding of C60 fullerene and demonstrated that the selective sensitivity of this material to the presence of Cu2+ and Pb2+, resulting in variations of the fluorescence intensity and optical absorbance, is related to nanoparticle aggregation processes. This mechanism occurs through coordination of the metal ions and, above a certain ion concentration, leads to precipitation of the carbon material that reduces the metal content in solution. The effect has been characterized by optical measurements while Atomic Absorption Spectroscopy have been carried out for a precise assessment of the real ion concentration in solution.We have synthesized two-dimensional carbon nanoparticles by oxidative unfolding of C60 fullerene and demonstrated that the selective sensitivity of this material to the presence of Cu2+ and Pb2+, resulting in variations of the fluorescence intensity and optical absorbance, is related to nanoparticle aggregation processes. This mechanism occurs through coordination of the metal ions and, above a certain ion concentration, leads to precipitation of the carbon material that reduces the metal content in solution. The effect has been characterized by optical measurements while Atomic Absorption Spectroscopy have been carried out for a precise assessment of the real ion concentration in solution.

© 2019 The Royal Society of Chemistry. A rational design of a high-performance cathode for proton-conducting solid oxide fuel cells (SOFCs) is proposed in this study with the aim of improving the hydration properties of conventional perovskite cathode materials, thus leading to the development of new materials with enhanced proton migration. Herein, potassium is used to dope traditional Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), which is demonstrated to be a beneficial way for improving hydration, both experimentally and theoretically. The theoretical study was needed to overcome practical limits that hindered direct hydrogen mobility measurements. The novel material Ba0.4K0.1Sr0.5Co0.8Fe0.2O3-δ (BKSCF) shows a lower overall proton migration energy compared with that of the sample without K, suggesting that K-doping enhances proton conduction, which shows an improved performance by extending the catalytic sites to the whole cathode area. As a result, a fuel cell built with the novel BKSCF cathode shows an encouraging fuel cell performance of 441 and 1275 mW cm-2 at 600 and 700 °C, respectively, which is significantly higher than that of the cell using the pristine BSCF cathode. This study provides a new and rational way to design a perovskite cathode for proton-conducting SOFCs with high performance.

Solid oxide fuel cells (SOFCs) represent the most efficient devices for producing electrical power from fuels. The limit in their application is due to the high operation temperature of conventional SOFC materials. Progress is made toward lower operating temperatures using alternative oxygen-ion conducting electrolytes, but problems of stability and electronic conductivity still remain. A promising alternative is the use of chemically stable proton-conducting Y-doped BaZrO3 (BZY) electrolytes, but their practical applications are limited by the BZY's relatively low performance. Herein, it is reported that deposition by impregnation of cathode nanoparticles on BZY backbones provides a powerful strategy to improve the BZY-based SOFC performance below 600 °C, allowing an outstanding power output for this chemically stable electrolyte. Moreover, it is demonstrated that keeping the nanostructure is more important than keeping the desired chemical composition. The proposed scalable processing method can make BZY a competitive electrolyte for SOFC applications.

Proton-conducting oxides offer a promising electrolyte solution for intermediate temperature solid oxide fuel cells (SOFCs) due to their high conductivity and low activation energy. However, the lower operation temperature leads to a reduced cathode activity and thus a poorer fuel cell performance. La0.8Sr0.2MnO3−δ (LSM) is the classical cathode material for high-temperature SOFCs, which lack features as a proper SOFC cathode material at intermediate temperatures. Despite this, we here successfully couple nanostructured LSM cathode with proton-conducting electrolytes to operate below 600°C with desirable SOFC performance. Inkjet printing allows depositing nanostructured particles of LSM on Y-doped BaZrO3 (BZY) backbones as cathodes for proton-conducting SOFCs, which provides one of the highest power output for the BZY-based fuel cells below 600°C. This somehow changes the common knowledge that LSM can be applied as a SOFC cathode materials only at high temperatures (above 700°C).

TiO2 coatings on AA6082 aluminium alloy were obtained at low temperature (80 and 100°C) by the sol-gel dip-coating technique starting from titanium tetra-isopropoxide solution in ethyl alcohol. The preparation was carried out in the presence of acetic acid with both functions of catalyst and chelating agent. The curing temperatures used for these coatings are between 80 and 100°C, low enough to make such coatings suitable to incorporate additives such as organic inhibitors or polymeric nanoparticles. The coated samples were characterised by scanning electron microscopy and energy-dispersive spectroscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy (EIS). Compact coatings with a thickness of 500 nm, consisting of amorphous and nearly stoichiometric titanium dioxide, were obtained. EIS results revealed an effective corrosion protection of the substrate for more than 120 h of immersion in 3.5 wt-% NaCl aqueous solution.

High temperature proton conducting oxides, due to their lower activation energy for proton conduction, can achieve high conductivity at relatively low temperatures (500-700 °C). Though BaZr0.8Y0.2O3-δ (BZY) perovskite exhibits good chemical stability and high bulk conductivity, high grain boundary resistance decreases its total conductivity. This work focuses on substitution of Zr4+ with Ni2+ in the perovskite B-site in a targeted fashion in order to promote the sinterability of BZY. Powder X-ray diffraction analysis showed the formation of single phases for Ba0.8-xY0.2NixO3-δ compositions up to x = 0.04. Scanning electron microscopy (SEM) image analysis demonstrated that densification is promoted by the increasing Ni-content, reaching a fully dense microstructure for Ba0.76Y0.2Ni0.04O3-δ (BZYNi04). An anode supported single cell based on BZYNi04 electrolyte showed superior power performance, achieving 240 and 428 mW cm-2 at 600 and 700 °C, respectively.

Full ceramic anodes have been developed over the last decade as an alternative to the state-of-the-art Ni/YSZ cermet. The objective is to overcome the technical limitations of the cermet, especially in high fuel utilization operational mode, when hydrocarbon fuels are used, or in systems where rapid heat up is required. Numerous oxide compositions were proposed and investigated. (La,Sr)Cr0.5Mn0.5O3(LSCM) perovskite has been reported as a very promising anode material because of its high tolerance to carbon and sulfur, and its redox and thermal cycling stability. However, similarly to other oxide anode materials, its overall performance still needed further improvement to match that of Ni/YSZ. The relatively low performance of LSCM compared to Ni/YSZ, used to be attributed to its relatively low electronic conductivity. Recently, we have reported that the pre-coating LSCM with Ni nitrate results in a considerable decrease in the anodic polarization resistance and activation energy. Ni dissolves in the perovskite phase at high temperature under oxidizing atmosphere, and then exsolves in the form of nanoparticles under reducing atmospheres. This type of anode composition with split functionalities (ionic conduction, electronic conduction, and catalytic activity) gives a unique opportunity to investigate the specific influence of each of the above functions on the anodic mechanisms and performance. In this work, electrochemical impedance spectroscopy was used to characterize anode compositions containing LSCM and different levels (15, 40, and 60 wt%) of gadolinia doped ceria (CGO), with and without additional submicron Ni, as well as Ni nanoparticles exsoluted from pre-coated larger LSCM particles. Impedance measurements were performed in a three electrode – half cell configuration from 700 to 900°C under two flow rates of 3% wet H2(50 and 150 ml/min). At 900°C and under 150 mL/min of 3% wet H2, lower values of the polarization resistance (Rp) were measured for the samples containing CGO compared to pure LSCM ones. The Rp showed a slight decrease when the content of CGO was increased (15 to 40 and 60 wt%). This was characterized by a decrease of the high frequency part of the impedance diagrams, likely due to the higher ionic conductivity brought by the addition of CGO. The addition of 5 wt% of submicron Ni to LSCM-CGO led to a remarkable decrease in Rp. This effect was even more spectacular for the samples containing 5 wt% of exsoluted Ni nanoparticles, characterized by a decrease of the whole impedance diagram, and especially the high and the middle frequency parts, which suggests an enhancement of the electrochemical processes related to anode charge transfer. Further analysis of the impedance diagrams, measured for the above anodes at different temperatures and gas flow rates, is in progress in order to define the effect of different anode functionalities on the anodic processes involved, and thus its overall performance.

One of the main problems for the deployment of intermediate-temperature solid oxide fuel cells (IT-SOFCs) is their chemical stability, since most of SOFCs contain alkaline-earth metal elements (Ba, Sr and Ca) that easily react with CO2 forming carbonates. To tackle this problem, we performed a systematic investigation of a series of Ni0.7Co0.3O–Ce0.8Sm0.2O1.9 (NC3O-SDC) composite cathodes, which are CO2-stable and alkaline-earth-free compounds. In this work, NC3O-xSDC (with x = 0-60 wt.%) were synthesized by self-propagating combustion method and investigated as new cathode materials for oxygen-ion conducting SOFCs. The thermal stability and phase structure of NC3O polycrystalline powders were studied using TG-DTA and XRD analysis, which confirmed that NC3O is chemically compatible with SDC. The electrical conductivity and thermal expansion of the NC3O-xSDC samples were measured. The electrochemical properties of NC3O-xSDC/SDC/NC3O-xSDC cells were studied using electrochemical impedance spectroscopy measurements. Among the NC3O-xSDC series, NC3O-30SDC showed a minimum in cathode polarization resistance, being 0.071 Ωcm2 at 800. A maximum power density of 200 mWcm-2 at 600 was obtained using anode-supported SOFCs.

International audience; Bare and Al2O3-coated austenitic steel samples are exposed to lead-fast-reactor relevant corrosive conditions.Selective leaching of Ni, Mn and Cr is observed in bare samples exposed to high temperature stagnant lead(550 DC, 10et8722;8 wt.percent oxygen, 1000 and 4000 h). By contrast, corrosion is not observed in either pristine (4000 h)or irradiated (1000 h) coated samples. Further characterization and testing methods include SEM, TEM, STEM,EDS, cyclic nanoimpact, microindentation, scratch, and thermal cycling. Overall, the results show that thecoatings retain structural integrity under the conditions investigated, which is a crucial prerogative for corrosionprotection with ceramic coatings.

The impregnation method has been considered as one of the most successful techniques for the fabrication of highly efficient electrodes for solid oxide fuel and electrolysis cells (SOCs) at the lab scale. However, because the impregnation is usually performed manually, its irreproducibility remains a major problem that can be solved by using controllable techniques, such as inkjet printing. In this paper, lanthanum strontium manganite (LSM)/yttria stabilized zirconia (YSZ) air electrodes were prepared by infiltrating YSZ porous bodies with LSM precursor solution using inkjet printing, followed by annealing at 800°C for 2 hours. XRD analysis confirmed the formation of the LSM phase, which was in the form of nanoparticles with size in the 50-70 nm range on the YSZ walls, as revealed by FEG-SEM observations. The effect of printing parameters on the distribution of the impregnated phase was investigated and discussed.

La0.8Sr0.2Ga0.8Mg0.2O3-delta (LSGM) perovskite oxide was selected as electrolyte to fabricate reduced-temperature solid oxide fuel cells (SOFCs). Porous/dense ceramic bilayers were optimized by using different pore forming agents. Reduced temperature (700 degrees C) infiltration method was employed to obtain anodes with nano-sized metal oxidation catalysts. The type and amount of porogen necessary to get a proper anodic porosity were evaluated together with the amount of infiltrated Ni catalyst to obtain promising electrochemical results. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

We present an ab initio investigation of the interaction between methane, its dehydrogenated forms and the cerium oxide surface. In particular, the stoichiometric CeO2(111) surface and the one with oxygen vacancies are considered. We study the geometries, energetics and electronic structures of various configurations of these molecules adsorbed on the surface in vacuum, and we extend the analysis to realistic environmental conditions. A phase diagram of the adsorbate–surface system is constructed and relevant transition phases are analyzed in detail, showing the conditions where partial oxidation of methane can occur.

Solid oxide electrolysis cells (SOECs) are expedient to solve the site-specific and intermittent problems for current renewable energies, such as solar, wind and tidal power, as SOECs can convert these renewable energies into chemical energy in the form of H2 that is clean and easily to be transported. Most of the studies on SOECs are focused on oxygen-ion conducting SOECs, using mainly yttria-stabilized zirconia (YSZ) as electrolyte. However, problems such as the dilution of produced H2, high temperature operation, and oxidation of Ni-based fuel electrode occur, which the use of proton-conducting SOECs can circumvent. In addition, the high conductivity of proton-conducting oxides with respect to YSZ enables proton-conducting SOECs operating at intermediate temperatures [1]. The few works reporting on proton-conducting SOECs show the use of BaCeO3-based electrolytes, which has been demonstrated to be chemically unstable in H2O. Although proton-conducting BaZrO3-based materials are the most promising electrolyte candidates for proton-conducting SOECs due to the excellent chemical stability and high bulk conductivity [2], their processing difficulties due to poor sinterability and high-resistive grain boundaries prevented the deployment in SOEC devices. In this report, we pioneeringly used BaZrO3-based electrolytes for SOECs, demonstrating that tailoring the electrolyte and electrode materials results in further improving the electrolysis cell performance. Anode supported BaZr0.9Y0.1O3-δ (BZY) electrolyte films were fabricated using an ionic diffusion method [3]. Both thermodynamic calculation and experimental results suggest that BZY has an excellent chemical stability in H2O, which is critical for practical applications. A current density of 119 mA cm-2 was obtained at 600°C, with an applied voltage of 1.65 V for the electrolysis cell, which is comparable or even higher than that for proton-conducting SOECs with BaCeO3-based electrolyte at similar conditions, while BZY electrolyte offers much better chemical stability. This cell also operated at 600 oC for more than 80 h without any obvious degradation, while the BaCeO3-cells are reported to only last tenths of minutes or a few hours [4]. To improve the cell performance, BaZr0. 7Y0. 2Pr0.1O3-δ (BZPY10), which is a more conductive proton-conducting electrolyte material, wass used for the SOEC. With La0.8Sr0.2MnO3-δ (LSM)-BZPY10 composite air electrode, the SOEC with BZPY10 electrolyte reached a current density of 576 mA cm-2 with an applied voltage of 1.6 V at 600 oC. This cell performance is much improved compared with the above discussed BZY cell. Further cell performance improvement was achieved by tailoring the air electrode material with BaZr0. 5Y0. 2Pr0. 3O3-δ (BZPY30), which is a mixed protonic-electronic conductor rather than a pure protonic conductor [5]. By coupling BZPY30 with LSM, the triple phase boundary (TPB) is much improved due to the mixed conducting behavior of BZPY30, which is beneficial to the reaction. As a result, the cell with BZPY30-LSM air electrode produced a current density of 1007 mA cm-2 with an applied voltage of 1.6 V at 600 oC. An obvious cell performance improvement is obtained with the tailored electrode. Reference s L. Bi, S. Boulfrad and E. Traversa, Chem. Soc. Rev., 2014, 43, 8195-8300. D. Pergolesi, E. Fabbri, A. D'Epifanio, E. Di Bartolomeo, A. Tebano, S. Sanna, S. Licoccia, G. Balestrino and E. Traversa, Nature Mater., 2010, 9, 846-852. L. Bi, E. Fabbri, Z. Q. Sun and E. Traversa, Energy Environ. Sci., 2011, 4, 409-412. L. Bi, S.P. Shafi and E. Traversa, J. Mater. Chem. A, 2015, DOI: 10.1039/c4ta07202b. E. Fabbri, L. Bi, D. Pergolesi and E. Traversa, Energy Environ. Sci., 2011, 4, 4984-4993.